Authors: Tomesc, Liviu; Dobra, Petru; Abrudean, Mihail

Abstract: Harmonics distortion, power sag or power swell are only few phenomena that can influence power quality. These issues are becoming a serious concern for many energy users, as they can cause serious damage to the electrical equipment. This paper presents a low-cost power quality analyzer based on frequency analysis, as a solution for constant measuring and monitoring of specific parameters.

Keywords: fast Fourier transforms,frequency signal analysis,signal processing,microprocessor,harmonics,frequency measurements

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00025

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 157-162

Authors: Balan, Radu; Hancu, Olimpiu; Lupu, Eugen

Abstract: Electric arc furnaces (EAFs) are commonly used in steelmaking and in smelting of nonferrous metals. Usual EAFs work at power levels from 10MW to 100MW. The power level is directly correlated to production throughput, so it is important to control the EAF at the highest possible average power with a low variance to avoid breaker trips under current surge conditions. To obtain the electric arc, usually there are used three graphite electrodes. The power level depends by the positions of the electrodes. As a result, the realization of a competitive control system is very important because it led to reduction of the energy consumption, pollution, and increases the safety of the process. This paper presents some aspects concerning modeling of the electric arc, modeling of the EAF electrical system, modeling and adaptive control of EAF process - hydraulic control system of electrode position. Finally, a simulation application is presented.

Keywords: modelling, simulation, electric Arc furnace, adaptive control

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00026

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 163-168

Authors: Dobriceanu, Mircea; Bitoleanu, Alexandru; Popescu, Mihaela; Vladu, Gabriel

Abstract: Evolution and large scale spreading of the computational techniques allowed the design and realization of some acquisition, processing, storing and sending data taken from the process equipments to a superior level - dispatcher. In this way, it is presented a data acquisition equipment for energetic measures which is incorporated in a dispatching system aiming the monitoring and storing of electrical measures which are taken from electrical cells which compose the supervised electrical station. There is shown the system architecture underlining the taken signals, transducers used and the component elements of the system: Local data acquisition equipments (LDAqE), Local data acquisition equipments synchronization subsystem, Data communication subsystem and Processing, storing and data displaying subsystem.

Keywords: data transmission,energy system management,measurements,transducers

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00027

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 169-173

Authors: Olaru, Virgil; Enculescu, Cosmin; Enache, Alexandru; Staicu, Dorin; Staicu, Gabriela; Cepisca, Costin

Abstract: The paper describes a project found out in the progress and based on a patent that was awarded with the bronze medal at Eureka World Inventions Salon, Brussels, 2004. The project result is to offer drinking water supply at constant pressure to each customer. For this are used monitoring and control solutions. As component part of ICT and found out in a continuous development, the Internet represents one of the communication solutions used in the project.

Keywords: pressure control,pressure transducers,communication networks,efficiency,energy control,economic system,variable delivery pumps,inverter drives,speed control

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00028

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 174-176

Authors: Stancel, Eugen; Cadis, Magdalena; Schiau, Cristina; Ghiran, Ovidiu; Stoian, Ioan

Abstract: Based on the resources and capabilities of the implemented SCADA system of the hydroelectric plant this paper describes temperature monitoring techniques for collecting, archiving, and analysing the data required by the operator, as well as generates predefined reports for maintenance management. The hardware and software support of SCADA system offer the way to investigate the real-time functioning status of hydro power plant generating units and create a tool to identify the stress induced by electrical and thermal condition.

Keywords: controllers,hydrogenerators,expert system,monitoring,hydroelectric systems

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00029

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 177-181

Authors: Vladu, Gabriel; Fetoiu, Marius; Dobriceanu, Mircea; Popescu, Mihaela; Dobriceanu, Dan Octavian

Abstract: The extension of computational technique for the generalization of automatics, information and process monitoring involve the conception and materialization of complex data acquisition equipments, processing, memorizing and sending data taken from those processes at a higher level - dispatcher. In this way, it is presented data acquisition equipment for energetic measures which is incorporated in a dispatching system aiming the monitoring and storing of electrical measures which are taken from electrical cells which compose the supervised electrical station. There are distinguished the component elements of the monitoring system: Local data acquisition equipments (LDAqE), Local data acquisition equipments synchronization subsystem, Data communication subsystem, Processing, storing and data displaying subsystem and the software for data processing at the dispatcher level and also at the local data acquisition equipment level.

Keywords: data transmission,energy management systems,measurement transducers,Daq,dispatcher

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00030

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 182-187

Authors: Doheijo, Enrique; Vladut, Gabriel; Matei, Virginia; Cojocaru, Camelia; Nunez, Laura; Lopez, Jose Ramon; Cappelo, Francesco

Abstract: e-Networks represent now an important and modern educational tools and solutions that bring together geographically distant research groups, allowing them to share data, documents, video and audio presentations, while integrating their computational and laboratory resources. The recent created EIFN Network, are implemented as a new generation communication service, not as a simply Worldwide Web application. So, they employ a sophisticated access framework, a communication infrastructure able to support multimedia flows and a component-based software construction. As the Internet is turning into a really multiservice network with a steady increase in bandwidth and decrease in response time, the environment becomes more suitable for implementations such as e-Network.

Keywords: innovation,network,technology transfer,energy

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00031

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 188-192

Authors: Balan, Horia; Botezan, Aurel; Tirnovan, Radu; Vadan, Ioan; Iacob, Ana

Abstract: Inverters with capacitive loads or with additional series capacity and which assure a capacitive current through series circuit usually determine observance of return time, and reactive power delivered by load is adequate for commutation of thyristors, not be necessary auxiliary turn-off circuit. These types of inverters are known below name inverters with load commutation.

Keywords: inverter,hybrid commutation,turn-off LC circuit

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00032

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 193-196

Authors: Lungoci, C.; Becherif, M.; Miraoui, A.; Helerea, E.

Abstract: The on-board energy system permits the storage/delivery energy in electrical vehicles. It can use different energy devices working together, like batteries and supercapacitors. The energetic performances of batteries make them efficient, but for supplying pulsating loads, supercapacitors must be added. In this paper, the design of the system is presented and the dynamic model is described using the Port-Hamiltonian formalism. The Passivity-Based Control strategy is proposed according to achieve the best energy management of the system. Simulation results of the system processes are presented in order to prove that the model and the control strategy applied can ensure the global system stability.

Keywords: electrical vehicle,supercapacitors,batteries,passivity-based control

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00033

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 197-202

Authors: Morar, Alexandru

Abstract: The papers presents a high performance speed and position control system for separately-excited D.C. motor, which was designed and performed with a dedicated integrated circuits (L290, L291, L292), made by SGS-THOMSON Microelectronics Company. The L290, L291 and L292 together form a complete microprocessor-controlled (microcomputer chips) DC motor servo positioning system that is both fast and accurate with an adequate software. The papers presents a description of the system, detailed function descriptions of each device and application information.

Keywords: D.C. motor,optical encoder,switch mode driver,position feedbak,tacho velocity feedbak

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00034

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 203-208

Authors: Ordean, Mircea; Dulf, Eva-Henrietta; Festila, Clement

Abstract: An important amount of the Electric Power Generation (EPG) company costs is given by the maintenance costs. The implementation of a SCADA system in the hydro-power plant enables the improvement of the maintenance, management and general control strategy. Based on the new and large possibilities of the SCADA-systems, the actual paper presents (in accord to the legal frame) the fundaments for the implementation of the Operational Management System (OMS) for the Hydro-electric Power Plant belonging to the general system of the Hydraulic Power Plant. The target of the OMS is to create a general Hydro-power Plant Dispatcher (HPD) for the whole chain of Hydroelectric Stations from the Somes-river (Ordean, 2005). The local Information Net of each Power Station (already in operation) is connected to the HPD in order to supervise the station operation, but also to control, directly through HPD, the equipment of the Hydro-electric station.

Keywords: SCADA system,hydro-power plants,hydro-electric stations

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00035

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 209-212

Authors: Sanislav, Teodora; Capatana, Dorina; Dancea, Ovidiu

Abstract: In the SCADA system monitoring, control and over-limit alarm processes from the hydroelectric power plants cascade (on the Cris river) have been obtained a large amounts of historical data stored in a database. But in their preliminary form these data don't mean a performance management. Data mining techniques applied over historical acquired data are used to extract hidden management information directly from the SCADA system's database records. This paper presents a data mining framework for the historical data of an industrial measurement and control system and establishes a data mining flow.

Keywords: data acquisition,data flow analysis,data processing,databases,hydroelectric systems,control system,management system,and decision trees

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00036

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 213-218

Authors: Balaj, Aliodor; Ungureanu, Gicu; Covaciu, Florin

Abstract: In each hydroelectric power station, one of the outstanding systems is the power channel, which provides water flow to the hydroelectric power generators. On this power channel, there are two or more special valves that can interrupt the flow in specials conditions. In this specific application, there are two butterfly valves and the two command systems, placed together into a special underground room, called "valve house". The function of the each system is to allow the water flow reach the generators by keeping the valves opened (0 - 5 degrees) and to avoid the overflow of the underground power station in some cases. These two systems are conected by electrical signals, in order to increase safety in use by detecting malfunctions and to close at least one valve.

Keywords: power channel,butterfly valves,power station,redundancy

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00037

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 219-223

Authors: Campeanu, Radu; Margineanu, Ioan; Suciu, Constantin; Rogoz, Adrian

Abstract: The measurement of the relative position of a dam point is an important issue for the observation of its state. The goal of this paper is to present a measurement system of the relative position, based on the trilateration method. The distances are measured with laser telemeters of high precision, which are connected to a RS-485 net or directly to a data base with SIEMENS programmable logic controller. A Kalman filter has been used in the case of each measurement for ensuring a good precision. The system is part of a developed contract by IPA Cluj - Napoca.

Keywords: positioning systems,kalman filters,data acquisition,measurement noise,computer applications and computer simulation

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00038

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 224-227

Authors: Enyedi, Sz.; Miclea, L.; Valean, H.; Stoian, I.

Abstract: This paper presents a project which uses software agents as means for more efficient monitoring, testing and diagnosis of a complex heterogeneous system - multiple hydroelectric power plants connected in a chain on a river. The agent system will be superimposed over the existing SCADA control and monitoring network and will increase performance, efficiency and stability in the existing system.

Keywords: agents,monitoring,automatic testing,diagnosis,power stations,complex systems

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00039

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 228-233

Authors: Gordan, Mihaela; Dancea, Ovidiu; Vlaicu, Aurel; Stoian, Ioan; Tsatos, Odysseas; Oltean, Gabriel

Abstract: Hydro dams are very important economical and social structures that have a great impact on the population living in surrounding area. Surveillance of dam status consists of a complex process which involves data acquisition and analysis techniques, implying measurements from sensors and transducers and visual inspection. To enhance the visual inspection process made by experts, we propose a computer vision technique that will allow assessment and quantification of water infiltrations inside the dam wall, based on infrared and visible spectrum image analysis and data fusion techniques.

Keywords: infrared imaging,data fusion,dam monitoring,image processing

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00040

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 234-239

Authors: Letia, Tiberiu; Astilean, Adina; Avram, Camelia; Chindris, Mircea; Cziker, Andrei; Hulea, Mihai

Abstract: A new distributed approach for monitoring the voltage events (sags and overvoltage) in electric power system is proposed. The distributed monitoring system is implemented on a set of microcontrollers connected to personal computers that are linked through Internet. The microcontrollers endowed with voltage transducers implement information agents that communicate to a software multiagent-agent system when voltage events occur. The users of the power system can get information about events occurred during a period of time.

Keywords: electric power systems,monitoring elements,discrete event systems,real-time systems,information systems

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00041

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 240-245

Authors: Ungureanu, Petre; Veres, Ciprian

Abstract: The classical Thermal Loop Test up to national standards of prophylactic measurement for high voltage rotating machinery was improved by the intermediate of thermo-graphic inspection with a last generation of INFRARED THERMOVISION CAMERA. The method generates thermo-graphic maps by intermediate of a dedicated software of the internal cylindrical surface of the magnetic core of the rotating machinery. The thermo-graphic maps are generated in strictly identical condition at the start of the generator, as well as at the major planned outages after 5, 10, 15, 20 years of functioning. The proposed method of testing allowed the users to compare the thermo-graphic maps and to put in evidence the "thermal hot spots" (respectively the magnetically failures) and their evolution in time and gives the users the possibility to establish the moment of partial or complete replacement of the iron core.

Keywords: power generators,magnetic core diagnosis,infrared thermo-vision,temperature mapping

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00042

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 246-250

Authors: Iancu, Eugen

Abstract: Early detection of a fault or damage at power plants is crucial for their control and maneuvering. In this paper, the author proposes a practical design method useful in the supervising of the system in presence of process faults. The fault detection and isolation (FDI) problem is an inherently complex one. The immediate goals is to preserve the stability of process and, if is possible, to control the process in a slightly degraded manner.

Keywords: fault diagnosis,fault detection,fault isolation,fault tolerance,analytical redundancy,control system

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00043

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 251-256

Authors: Oprisescu, Doru

Abstract: This presentation refers to the monitoring and diagnosis system elaborated by IPA S.A. for the Movileni hydroelectric power plant, containing two 6,5 kV and two 10,5 kV Kaplan hydroelectric units.

Keywords: hydroelectric power plants,Kaplan,monitoring

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00044

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 257-259

Authors: Vinatoru, Matei; Iancu, Eugen; Canureci, Gabriela; Maican, Camelia

Abstract: This paper developing two inputs and two outputs control systems a structure for fault detection and localization using actuators fault detection that can inform the operator about the faults following actuators blocking or changes in the burning process and heat transfer conditions and developing a simplified lumped parameters model that approximates the distributed parameters structure of steam superheaters.

Keywords: fault detection and isolation,two inputs,two outputs,control systems

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00045

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 260-265

Authors: Vinatoru, Matei

Abstract: For existed plants with minimum equipments to automatic control it is necessary to increase the safety control by using digital equipments for distributed control using modern methods for monitoring and control. It is necessary to improve the methods for early detection of process and equipment faults. This study reports the implementation test details and methods for fault detection in terms of benefits for the power plant.

Keywords: fault detection and isolation,analytical method,multivariable control systems

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00046

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 266-271

Authors: Moga, Daniel; Rusu, Corneliu; Dumitrean, Mihai; Moga, Rozica; Muresan, Adrian

Abstract: A low cost solution is proposed for measuring the vibrations induced by rotating parts. Attaching very sensitive acceleration sensors allows measuring these vibrations. The signal acquired from the sensors will present a periodic behaviour which is correlated to the rotational speed of the axle. Beside the indication of the RPM of the axle, more detailed information can be extracted using signal processing techniques in order to determine the signatures associated with specific faults.

Keywords: vibration measurement,accelerometers,wireless sensors,analysis and diagnosis

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00047

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 272-275

Authors: Hadrian, Bogariu; Eva, Dulf; Clement, Festila

Abstract: Voltage sag is defined as a sudden reduction of supply voltage down 90% to 10% of nominal voltage, followed by a recovery after a short process time. A typical duration of sags, according to some standards, is 10 (msec) to 1 (min). Although more process equipments accept these voltage disturbances without notable consequences, there are sensible electronic schemes affected by voltage sags. The actual paper analyses the power quality delivered to an important manufacturer which uses some "critical equipment" and emphasizes the connections between voltage disturbances and difficult events registered by manufacturers. Because the "mitigation means" are expensive, the authors try to choose the optimal solution (price/quality).

Keywords:

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00048

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 276-281

Authors: Buzdugan, Livia

Abstract: In this paper a possible extension and the use of Taylor series for the numerical modelling and simulation of some processes which can be described in terms of second order partial derivative equations which depend on four independent variable is developed (Bellomo, and Preziosi, 1995; Farlow, 1982). One of these processes may be experienced in the field of pollutants dispersion. In power plants, stacks are usually not instrumented to measure pollutants emision, thus the available emission data is always very limited and often uncertain and imprecise. The mathematical models are developed to describe the air pollution dispersion from a power plant stack.

Keywords: partial derivative equations,state variables,Taylor series,numerical integration,pollutants dispersion

Digital Object Identifier (DOI): 10.3182/20070709-3-RO-4910.00049

Conference: First IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems (2007)

Location: Technical University of Cluj-Napoca, Romania

Start Date: Mon Jul 09 2007 - End Date: Wed Jul 11 2007

Page Numbers: 282-286